Key to species of South Korean Micropezidae

1. Leg coloration yellow or orange; wings without any markings; katepisternum with bristles not forming a vertical row of bristles posteriorly; surstylus present............................................................................ 2

- Overall body coloration dark brown, wings with fuscous discal band; katepisternum with a vertical row of bristles posteriorly; surstylus absent....................................................................................... 3

2. Head triangular in lateral view, without fronto-orbital bristles; short dorsal spines present on the middle and hind femora; all tergites black (Fig. 4C–D)...................................................... Micropeza soosi Ozerov, 1991

- Head globose in lateral view; without short spines on the dorsal side of middle and hind femora; tergites black with orange marking on posterior corner (Fig. 4A–B)....................................... Compsobata dentigera (Loew, 1854)

3. Middle and hind femora with four reddish brown rings; all tarsi white (Fig. 4E) … Mimegralla suzukiana (Matsumura, 1916)

- Middle and hind femora with yellowish brown preapical ring; middle and hind tarsi usually concolorous with dark brown femora.............................................................................................. 4

4. Male sternite 5 as in (Fig. 5A), female sternites 3–4 strongly reduced (Fig. 6C–D); pleural membrane dark brown with distinct triangular white region below T 3–4 in female................................. Rainieria triseta Li, Liu & Yang, 2012

- Male sternite 5 as in (Fig. 5B); all female sternites well developed; pleural membrane uniformly dark brown with pale region below T 3 in males, T 3–4 in females...................................... Rainieria tenebrosa Kim and Lee sp. nov.